Details disclosed herein merely offer background information regarding embodiments and are not applicable as prior art.
Streaming refers to the transmission of content, such as video or audio, from a server to a client over a network such as the Internet. Since data is processed as if water is flowing, it is called streaming. The server divides the data into a plurality of packets to be delivered to the client, and the client collects the packets received from the server, restores the packets to their original form, and plays them. At this time, playback and packet reception occur at the same time, and a series of related packets is called a stream.
In such a streaming service, an internet service server that desires to provide a streaming service transmits streaming data to a receiver in a unicast mode. Unicast is technique for transmitting streaming data to one receiver. In case of using unicast technique, the internet service server transmits duplicate same stream to all connected receivers. This invites a problem of causing excessive server load and unnecessary use of network resources due to redundant traffic. Another problem is that it is difficult to use a high-quality streaming service due to a delay in reception since a receiver uses a streaming service through a general internet network.
In recent years, multicast technique is attracting attention, in which receivers are managed as a group and data is transmitted to a limited number of receivers belonging to the group. In a multicast mode, when the internet service server that serves as a source transmits one streaming data, a plurality of routers capable of operating according to a multicast protocol copy and deliver the streaming data.
Compared with the unicast mode, the multicast mode can reduce the overhead of concentrating on the internet service server and also does not transmit duplicate streaming data on the network. This allows more efficient utilization of network resources.
However, even though there is a need to provide a streaming service in such a multicast mode, the inventor(s) has experienced that the internet service server that does not construct its own multicast network has many problems in application.